Method of fabricating a thin film transistor in which the channel region of the transistor consists of two portions of differing crystallinity

摘要

A semiconductor device which is excellent in reliability and electrical characteristics. The semiconductor device is formed on an insulating substrate. A channel region is formed between a source and a drain by the voltage applied to a gate electrode. The channel region, the source, and the drain are fabricated from a semiconductor having a large mobility. The other regions including the portion located under the channel region are fabricated from a semiconductor having a small mobility.